At present, as the amount of data to be handled increases, the necessity for a data recording apparatus that records data on a magnetic tape as a means for storing a large amount of data is becoming strong. On a record medium that uses such a magnetic tape, unlike with a disc type record medium, data is almost sequentially recorded.
At this point, longitudinal tracks are formed at the upper and lower portions in the width direction of the tape. Between the upper and lower longitudinal tracks, helical tracks are formed so as to effectively use the magnetic tape. The helical tracks are formed by a helical scan head in such a manner that a head mounted on a rotating drum is rotated with an angle to the traveling direction of the tape.
The upper longitudinal track is a control track for recording control pulses. On the other hand, the lower longitudinal track is a time code track for recording time codes. The time code represents the longitudinal position of the tape (namely, the physical ID of the tape). For example, the time code is recorded on every twelfth helical track. When the apparatus reads a time code, it can detect the current position of the head. As an example of the time code, SMPTE time code is used.
A magnetic tape of very large capacity type such as 42 Gbyte type is used. Thus, the magnetic tape is normally used with a plurality of separated areas. The separated areas are normally referred to as partitions or volumes. At the beginning of each partition, header information that represents the beginning thereof is written. With the partitions, one tape can be used as a plurality of tapes.
When the magnetic tape is initialized or the above-described partitions are formed thereon, data areas for managing the contents recorded on the tape are formed. For example, a VSIT (Volume Set Information Table) that is an area for managing information of partitions recorded on the tape and a DIT (Directory Information Table) that is an area for managing the partitions. These areas are important for managing data on the entire tape.
Thus, when data particularly in the VSIT area is lost, the data on the tape may not be used again. In addition, even if data can be restored from such a tape, since all the data recorded on the tape should be read, it will take a very long time. Thus, if an error takes place while writing or reading data to/from these areas, a write/read retry process should be required.
In the management information such as the VSIT and DIT, the VSIT for recording the management information of the entire tape is read just after the tape is loaded to the data recorder. Thus, the VSIT should have been recorded at a predetermined position of the start portion of the tape. In other words, the VSIT should have been recorded at a predetermined physical ID position. Thus, when a read error of the VSIT takes place and the read process is retried, the VSIT is written to the position of the physical ID where the error has taken place. In addition, as to the DIT, if the write process is retried, the DIT is written to the position of the physical ID where the error has taken place.
If an error takes place while reading data from the tape, although many causes can be considered, the error may take place due to a physical damage on the tape (for example, a scratch on the tape). When the VSIT and DIT are rewritten to the positions where an error has taken place, as with the related art reference, the same error will sometimes take place.
In addition, even if the VSIT and DIT have been successfully written, they may not be correctly read.